The present invention relates to a seal for sealing the axial and radial gaps between adjacent turbine blades on a gas turbine rotor disk.
Turbine or compressor blades of gas turbine engines are, in known manner, attached to the periphery of a rotor disk. The blades typically comprise an airfoil blade portion, a platform, a shank and a root that fits into a correspondingly shaped slot formed in the periphery of the rotor disk. The shank usually has a narrower cross-section than that of the root and is located between radially extending stiffeners extending from the platform. The stiffeners, together with the root subtend two cavities, one on the lower surface and the other on the upper surface.
The mounting of the blade structures on the rotor wheel typically allow gas leaks between the side edges of adjacent platforms near the gas flow path and through gaps formed between adjacent stiffeners upstream and downstream of the turbine rotor disks. Also, as is well known in the art, known turbine blades and seals have dampers eliminating the vibration of the blades during rotation of the rotor disk.
It is known to install seal devices in the cavities wherein such devices are solid and fabricated from metal or plastic. However, such known devices do not totally seal the leaks, especially the axial leaks near the stiffeners. Due to the centrifugal forces during rotation of the rotor disks, the known seal devices are pressed underneath the platform of the turbine blades and only seal the gap between adjacent platforms near the gas flow.
To limit vibration of the gas turbine engine blades during operation, it is known to use vibration dampeners. Such vibration dampeners may consist of polymer balancing masses affixed underneath the platforms and extending into the cavities. Another known solution is to add additional parts, such as upstream and downstream plates or flanges.